Article 28 — Consequences of invalidity

1. An EU design which is declared invalid shall be deemed not to have had the effects provided for in this Regulation as from the outset. 2. Subject to the national provisions relating either to claims for compensation for damage caused by negligence or lack of good faith on the part of the holder of the EU design, or to unjust enrichment, the retroactive effect of invalidity of the EU design shall not affect: (a) any decision on infringement which has acquired the authority of a final decision and been enforced prior to the invalidity decision; (b) any contract concluded prior to the invalidity decision, in so far as it has been performed before the decision; however, repayment, to an extent justified by the circumstances, of sums paid under the relevant contract may be claimed on grounds of equity.